CRG Discussion Forum
Camaro Research Group Discussion => General Discussion => Topic started by: black69 on January 06, 2008, 11:22:44 PM
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I needed someone to check my logic on the fresh air hood. If there were 10K hoods produced on cars in 69, and the pace cars took up around 3700 of them, and the copos took up the remaining 700, would that mean roughly 5600 hoods were left to go towards the remaining SS cars (pace cars are ss cars) and Z28s?
That's my current logic. To me it is fairly rare to have a real cowl induction hood on a 69 if you look at the 5600 vs the total z28s + SS cars totals (around 55K?). Its like a 10% chance you would run across a real one.
Am I missing something?
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It also missed the first four months of production.
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COPOs may not be included in that total. The ducted hood was not listed on documentation as it was included with 9560 & 9561.
Don't forget Z10s-another 500 or so where ZL2 was a required option.
Otherwise, yes. A factory ducted hood 69 is rare. Most Z/28s were not built with one.
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thanks. I do wonder how much difference in peformance a fresh air hood provides over the standard hood. I wonder if a L78 with the hood would be any worse off against an L89 without the hood. Would the weight savings get canceled by the heated air coming through the radiator..just a question I had...
I know my 65 L78 425hp vette runs fairly different once it starts seeing more hot air feeding it and becomes sluggish, but with cold air it is just a blast to drive. The L78 camaro with the fresh air hood runs fine all the time and I have let it get pretty hot (210).
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The standard rule of thumb is that there's a 1% power gain for every 10*F reduction in intake air temperature.
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was there any pressure added as the air drafted off the base of the windshield with that hood? . And if so, are their horsepower rule of thumb numbers for that?
I am thinking with underhood temps brewing pretty high at a head to head drag, a L89 ss hood car would be closer than you think with a ZL2 L78 when the pedals went to the floor.
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COPOs may not be included in that total. The ducted hood was not listed on documentation as it was included with 9560 & 9561.
Don't forget Z10s-another 500 or so where ZL2 was a required option.
Otherwise, yes. A factory ducted hood 69 is rare. Most Z/28s were not built with one.
I'm wondering if maybe Chevrolet sold more of these hoods over the counter than as original equipment??
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was there any pressure added as the air drafted off the base of the windshield with that hood? . And if so, are their horsepower rule of thumb numbers for that?
Probably zero net effect from that; even forward-facing hood scoops didn't really do anything, as they're in stagnant boundary layer airflow. That's why the scoop on a Pro Stocker has the intake 18" above the normal hood surface.
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I heard from a Chevelle guru, that the ZL2 hood was worth about 10hp. I thinks it's anyone's guess.
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How can we know if we have an original hood or not? ???
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How can we know if we have an original hood or not? ???
The orginal hoods had "notch" on the side edges of the hood up near the hoods meet the windshield. The Repro hoods do not have that little notched out area and are smooth on the side edges.
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How can we know if we have an original hood or not? ???
The orginal hoods had "notch" on the side edges of the hood up near the hoods meet the windshield. The Repro hoods do not have that little notched out area and are smooth on the side edges.
Can someone post a pic of this notch? Thanks.
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Photos below - the hood with a straight line in the side flange at the rear is the repro, and the hood where that line is a "notch" is the GM hood.
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Thanks
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Is there any way to date an original hood?
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Is there any way to date an original hood?
There should be a Chevrolet "run number" on it somewhere, like there is on the fenders and header panel, but I haven't found one yet.
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Thx. It looks like I have a GM hood. Too bad it's on a 68, but I like it.
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Below, I hope is a nice run number reference. I have a 20 (car is built first week of june). original paint, sharp stamp number. Nice find tonight...
http://albums.photo.epson.com/j/ViewPhoto?u=3010288&a=32237566&p=76094361
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I have an 18. Car built the first week of May.
Kris
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I have a 6. That means what?
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I have a 6. That means what?
6th week of the year - mid-February.
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Thanks again JZ.
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Below, I hope is a nice run number reference. I have a 20 (car is built first week of june). original paint, sharp stamp number. Nice find tonight...
http://albums.photo.epson.com/j/ViewPhoto?u=3010288&a=32237566&p=76094361
I have a 06A Z28 with the factory cowl hood option and docs to prove it. I have the original hood and will be looking for this number on mine tomorrow. The problem with my original hood, is previous owner installed hood pins. Would you guys try and have this fixed to keep the original hood, or buy another GM hood? Thanks!
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fix it!
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fix it!
Thanks for the reply Kevin. I was concerned about repairing it due to heat warping it. They did not do the neatest job when drilling the holes either. It looks like when they first drilled they were about a half of a hole off and then had to enlarge the hole, this was all covered by the hood pin chrome ring of course. The inner structure is a little messed up as well. I am going to drive out to where my car is stored and look for this run number on the hood, I know its a little thing but I'm kinda excited to see if its there. God bless! Travis
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Below, I hope is a nice run number reference. I have a 20 (car is built first week of june). original paint, sharp stamp number. Nice find tonight...
http://albums.photo.epson.com/j/ViewPhoto?u=3010288&a=32237566&p=76094361
I have a 06A Z28 with the factory cowl hood option and docs to prove it. I have the original hood and will be looking for this number on mine tomorrow. The problem with my original hood, is previous owner installed hood pins. Would you guys try and have this fixed to keep the original hood, or buy another GM hood? Thanks!
I just returned from looking at my hood and cant believe it!, I have a 20 stamped in mine as well. Thats is so cool!! I will be trying to find a way to repair it.
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Mine has a number 12 on my 04A SS. I never knew about this number until I read it in this thread!
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I just returned from looking at my hood and cant believe it!, I have a 20 stamped in mine as well. Thats is so cool!! I will be trying to find a way to repair it.
Find someone who can TIG weld the holes, TIG can dial down the heat and not warp the metal.
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I bought a SS hood this year off E Pay, not sure of the year of the hood. It's is going on my 69 SS X66 car. I am tired of the cowl hood thing on every first gen you see these days. ::) I am also ditching
the rear spolier !
Any way, my hood find has "AA" stamped on it.
Comments ?
Mike
(http://i18.photobucket.com/albums/b107/m22mike/NovaSS1-08199.jpg)
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Any way, my hood find has "AA" stamped on it.
Comments ?
"Acme Aftermarket" ??? ;D
Paul
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::)
Mike
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My Hood has the notch in it as is indicated to be a GM Hood. But it does not have any stamping in the location you guys have stamps. Does this still make it a GM NOS hood? Can this difference between GM and repro be confirmed by anyone else as I guess there are several manufacturers of these repro hoods now. Please let me know what you all think. Thanks in advance
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My Hood has the notch in it as is indicated to be a GM Hood. But it does not have any stamping in the location you guys have stamps. Does this still make it a GM NOS hood? Can this difference between GM and repro be confirmed by anyone else as I guess there are several manufacturers of these repro hoods now. Please let me know what you all think. Thanks in advance
My GM ZL2 hood doesn't have a number stamped there either.
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John - Thanks for the reply. I was also hoping others might have been able to look at their known repro hoods to see if any of the repro manufacturers had now manufactured any so that they now looked like the original GM in the same area as the pics show or if my hood was in fact 100% sure an original NOS GM.... ;D
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my friend with a white 69 copo (yenko) was surprized that I found where this number was located, and went and found a number on his original hood! even new guys can contribute
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Just thought I'd throw this out. When I was ordering my 69 396-375 the salesman asked if I wanted a fresh air hood. I didn't know what it was , but said ok. It cost 79 dollars!
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My GM hood purchased from Classic Industries in the mid '90s.
No numbers or letters.
(http://img262.imageshack.us/img262/3683/cowlhood001sy3.th.jpg) (http://img262.imageshack.us/my.php?image=cowlhood001sy3.jpg)
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Just thought I'd throw this out. When I was ordering my 69 396-375 the salesman asked if I wanted a fresh air hood. I didn't know what it was , but said ok. It cost 79 dollars!
For that price I hope you ordered a couple of spares!! ;D
Paul
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i have read that the ZL 2 cowl induction gave 10 HP. i believe thats in the "camaro untold secrets" book. all Z/28 options were engineered by GM for trans am racing. the spoilers also were engineered so that they worked.
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MY CAR IS A JUNE 69 BUILD VIN #661XXX, AND THE COWL HOOD IS STAMPED 23.